Restructuring and Related Charges - Activities in Restructuring Accrual (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 01, 2016	Jul. 03, 2015	Jul. 01, 2016	Jul. 03, 2015	Dec. 31, 2015	Dec. 31, 2014
Restructuring Cost and Reserve [Line Items]
Product cost of revenue	$ 6	$ 0	$ (23)	$ 0
Restructuring and related charges	1,903	185	4,515	229
Total restructuring and related charges	1,909	$ 185	4,492	$ 229
Harmonic 2016 Restructuring Plan [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges			4,557
Adjustment to restructuring provisions			1,087
Cash payments			(1,799)
Non-cash write-offs			(246)
Foreign exchange gain (loss)			(5)
Ending Balance	3,594		3,594
Harmonic 2016 Restructuring Plan [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Total restructuring and related charges			200
Restructuring Reserve [Roll Forward]
Restructuring charges			246
Adjustment to restructuring provisions			0
Cash payments			0
Non-cash write-offs			(246)
Ending Balance	0		0
Harmonic 2016 Restructuring Plan [Member] | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Total restructuring and related charges			1,400
Restructuring Reserve [Roll Forward]
Restructuring charges	1,400		1,418
Adjustment to restructuring provisions			1,087
Cash payments			(468)
Non-cash write-offs			0
Ending Balance	2,037		2,037
Harmonic 2016 Restructuring Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Total restructuring and related charges	1,900		3,000
Restructuring Reserve [Roll Forward]
Restructuring charges			2,893
Adjustment to restructuring provisions			0
Cash payments			(1,331)
Non-cash write-offs			0
Foreign exchange gain (loss)			(5)
Ending Balance	1,557		1,557
Harmonic Two Thousand And Fifteen Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges					$ 2,200	$ 1,500
Harmonic Two Thousand And Fifteen Restructuring [Member] | Employee Severance [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance			264
Adjustment to restructuring provisions			(65)
Cash payments	(194)
Ending Balance	$ 5		$ 5		$ 264